Preheat oven to 350°; grease jumbo muffin cups (3 ½ inch in diameter and 2 inches deep) with butter or cooking spray and lightly flour them, knocking out the excess flour, or line them with baking papers.
In a bowl, stir the food coloring and cocoa powder together to make a smooth paste; set aside.
Using an electric mixer fitted with the paddle attachment, cream the butter and sugar on medium-high speed until light and fluffy, about 2 minutes.
Add in the eggs, one at a time, beating after each addition, then add the cocoa paste while continuing to beat.
Decrease mixer speed to medium and beat the batter for about 4 minutes.
In another bowl, sift the cake flour, all-purpose flour, salt, and baking soda together.
Stir the vanilla into the buttermilk (can be done in the measuring cup).
Add the flour in 3 increments alternately with the buttermilk in 2 increments, starting and ending with the flour; beat on medium speed just until ingredients are combined.
Add the sour cream and vinegar and beat on low speed until combined.
Fill the muffin cups ¾ full with batter.
Bake for 25-35 minutes, just until the cupcakes feel firm to touch and a pick comes out clean (do not overbake or the cupcakes will dry out).
Remove from the oven and let cool in the pans for 5 minutes, then unmold onto a wire rack and let cool completely before frosting.
Make the icing: in a bowl of an electric mixer fitted with paddle attachment, beat the butter, cream cheese, and powdered sugar on medium-high speed until light and fluffy. Beat in the mascarpone on very low speed until just combined (be careful; once you’ve added the mascarpone, excessive beating can make the frosting curdle).
Stir in the vanilla or mint extract.
Frost the top of each muffin with the icing; if desired, sprinkle the crushed peppermint candy evenly over the cupcakes.